Format this new partition as ext3. By default, this reserves 5% of the disk for root. To remove this reservation, with use "-m 0". This can be changed later with "tune2fs -m 0 /dev/sdc1".
Alternatively, one can use mkfs.ext4 instead of mkfs.ext3 to format the partition as ext4 which is backward compatible with ext3.
Now create a new mount point in /media..

mkdir /media/new_drive

Edit /etc/fstab to add the new drive, such as the line

/dev/sdc1 /media/new_drive ext3 defaults,user,rw 0 0

Now mount the new partition using

mount /media/new_drive

Use df to make sure the new drive is up and you have the right amount of free space